1. Field of the Invention
The present invention relates generally to air conditioning systems for use in a vehicles, vehicles comprising such air conditioning systems, and methods for driving a hybrid compressor of the air conditioning system. In particular, the present invention is directed towards vehicles, air conditioning systems, and methods for driving hybrid compressors, in which fluctuations in a driving torque of the vehicle is reduced.
2. Description of Related Art
Known hybrid vehicles include an engine, and an air conditioning system. The air conditioning system includes a hybrid compressor, and the hybrid compressor includes an electric motor. The hybrid compressor may be driven by the engine or the electric motor, or both.
A Known hybrid, variable displacement-type compressor, such as the hybrid, variable displacement-type compressor described in U.S. Pat. No. 6,247,899 B1, includes a drive shaft, a compression mechanism, and an electromagnetic clutch. The compression mechanism includes a swash plate. The electromagnetic clutch is coupled operationally to the engine, and the drive shaft is coupled operationally to the electromagnetic clutch and the electric motor. The drive shaft also is coupled operationally to the compression mechanism. Moreover, a driving force is selectively transmitted from the engine to the drive shaft via the electromagnetic clutch, and from the electric motor to the drive shaft.
A known hybrid, rotary-type compressor, such as the hybrid, rotary-type compressor described in U.S. Pat. No. 6,375,436 B1, includes a drive shaft a compression mechanism, and an electromagnetic clutch. The electromagnetic clutch is coupled operationally to the engine, and the drive shaft is coupled operationally to the electromagnetic clutch and the electric motor. The drive shaft also is coupled operationally to the compression mechanism. Moreover, a driving force is selectively transmitted from the engine to the drive shaft via the electromagnetic clutch, and from the electric motor to the drive shaft.
Other known hybrid compressors, such as the hybrid compressors described in Japanese Patent Application Nos. 2001-280630 and 2002-031644, include a first drive shaft, a second drive shaft, a first compression mechanism, a second compression mechanism, and an electromagnetic clutch. The electromagnetic clutch is coupled operationally to the engine, and the first drive shaft is coupled operationally to the electromagnetic clutch. The first drive shaft also is coupled operationally to the first compression mechanism. Similarly, the second drive shaft is coupled operationally to the electric motor and the second compression mechanism. Moreover, a driving force is transmitted from the engine to the first drive shaft via the electromagnetic clutch, or from the electric motor to the second drive shaft, or both. As such, the first drive shaft and the second drive shaft may be driven selectively, i.e., by the engine or the electric motor but not both, or simultaneously, i.e. by both the engine and the electric motor.
In air conditioning systems including such known hybrid compressors, when operation of the air conditioning system begins, a temperature of air dispensed from an evaporator of the compressor is greater than a first temperature. Subsequently, when the temperature of the air dispensed from the evaporator decreases to the first temperature he electromagnetic clutch is disengaged, such that the engine and the compressor transitions from active to inactive to prevent the evaporator from freezing. When the engine is active, the driving force of the engine is transmitted to the drive shaft to drive the compressor, and when the engine is inactive, the driving force of the engine is not transmitted to the drive shaft. Similarly, when the compressor is active, the compressor is driven to compress a refrigerant, and when the compressor is inactive, the compressor does not compress the refrigerant. Subsequently, when the temperature of the air dispensed from the evaporator increases from the first temperature to a second temperature, the electromagnetic clutch is engaged, such that the driving force from the engine is transmitted to the drive shaft, and the compressor transitions from inactive to active. When the compressor transitions from inactive to active, a load demanded by the compressor increases, which causes a driving torque of the vehicle to increase. Moreover, when the compressor frequently transitions from active to inactive and then from inactive to active, the driving torque fluctuates, which decreases the vehicle""s efficiency.
Therefore, a need has arisen for hybrid compressors which overcome these and other shortcomings of the related art A technical advantage of the present invention is that the driving torque of the vehicle fluctuates less frequently than in the known compressors.
According to an embodiment of the present invention, an air conditioning system for a vehicle comprises a hybrid compressor and an evaporator, and the vehicle comprises a first drive source. The hybrid compressor comprises a second drive source and a temperature sensor for detecting the temperature of air dispensed from the evaporator. The hybrid compressor is driven by the first drive source via an electromagnetic clutch or the second drive source, or a combination thereof. The electromagnetic clutch is disengaged and the second drive source is active when a temperature of the air dispensed from the evaporator is equal to a first predetermined temperature.
According to another embodiment of the present invention, a vehicle comprises a fist drive source and an air conditioning system. The air conditioning system comprises a hybrid compressor and an evaporator. The hybrid compressor comprises a second drive source and a temperature sensor for detecting the temperature of air dispensed from the evaporator. The hybrid compressor is driven by the first drive source via an electromagnetic clutch or the second drive source, or a combination thereof. The electromagnetic clutch is disengaged and the second drive source is active when a temperature of air dispensed from the evaporator is equal to a first predetermined temperature.
According to yet another embodiment of the present invention, a method for driving a hybrid compressor of an air conditioning system of a vehicle is provided. The vehicle comprises a first drive source, and the air conditioning system comprises an evaporator. Moreover, the hybrid compressor comprises a second drive source, and the hybrid compressor is driven by the first drive source via an electromagnetic clutch or the second drive source, or combination thereof. The method comprises the steps of engaging the electromagnetic clutch, detecting a temperature of air dispensed from the evaporator, and disengaging the electromagnetic clutch when the temperature of the air is equal to a predetermined temperature. The method also comprises the step of activating the second drive source. Specifically, the step of disengaging the electromagnetic clutch when the temperature of the air is equal to the first predetermined temperature, and the step of activating the second drive source, are performed simultaneously or substantially simultaneously.
Other objects, features, and advantages will be apparent to persons of ordinary skill in the art from the following detailed description of the invention and the accompanying drawings.